Cell membranes and excitation Flashcards Preview

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Flashcards in Cell membranes and excitation Deck (16)
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1
Q

What are the 2 types of excitable cells?

A

Muscle and nerve cells

2
Q

What are the 3 types of muscle cells and what is their function?

A

Smooth, skeletal and cardiac. Contraction

3
Q

What is a nerve cell called and what is its function?

A

Neurone. Conduction

4
Q

Describe the structure of a neurone:

A

A neurone has a cell body soma consisting of 5-7 dendrites. It then has an axon hillock which is where the AP starts. It then has the main axon which is wrapped in Schwann cells and nodes of ranvier. This then leads to a terminal bouton synapse.

5
Q

What is the transmembrane resting potential?

A

It is a form of stored potential energy which can be used to deliver an AP

6
Q

What leaks out mostly from the membrane out of a neurone?

A

Potassium

7
Q

Describe the NaKATPase pump:

A

Inside the cell 3Na+ ions will move out in place of 2K+ ions which will enter into the cell

8
Q

What is the electrogenic pump:

A

Net loss of one positive charge form the cytoplasm to maintain the electrical gradient

9
Q

What is the voltage within a neurone?

A

-70mV

10
Q

Why are voltage gated sodium channels slow to open and close?

A

So they have time to reset and so there is a gap in the AP

11
Q

What is the distribution of ions in the intra/extracellular fluid at rest?

A

The intracellular fluid has a high conc. of K and protein. The extracellular fluid has a high conc. of Na and Cl

12
Q

What are the 2 types of response from a stimulus:

A

Local - non-propagated and propagated disturbance

13
Q

What type of the response does the neurone work by?

A

All or nothing response

14
Q

Describe an action potential graph including ionic movement:

A

Action potential occurs and breaks the threshold
Na enters into the cell on initial increase
Depolarisation
As the graph plateaus the Na channels close and K channels open
As the graph decreases, Ca enters the cell and K leaves
As the graph hits -70mV again this is the absolute refractory period
There is then hyperpolarisation, the membrane resets

15
Q

Where does the AP start?

A

At the axon hillock

16
Q

What occurs at the nodes in myelinated axons

A

Saltatory conduction